/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: Fallback.java,v 1.2.4.1 2005/09/01 14:22:25 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;

/**
 * @author Morten Jorgensen
 */
final class Fallback extends Instruction {

  private boolean _active = false;

  /**
   * This element never produces any data on the stack
   */
  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    if (_active) {
      return (typeCheckContents(stable));
    } else {
      return Type.Void;
    }
  }

  /**
   * Activate this fallback element
   */
  public void activate() {
    _active = true;
  }

  public String toString() {
    return ("fallback");
  }

  /**
   * Parse contents only if this fallback element is put in place of
   * some unsupported element or non-XSLTC extension element
   */
  public void parseContents(Parser parser) {
    if (_active) {
      parseChildren(parser);
    }
  }

  /**
   * Translate contents only if this fallback element is put in place of
   * some unsupported element or non-XSLTC extension element
   */
  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    if (_active) {
      translateContents(classGen, methodGen);
    }
  }
}
